Core exercising machine

ABSTRACT

A collapsible exercise machine for strengthening the core muscles (transverse abdominal, internal obliques, external obliques, rectus abdominis, and erector spinae) includes a frame mounted on a base on which a user sits and manipulates an upstanding lever arm. A seat is convertible between two differently-angled positions for back extension or abdominal exercises. The lever arm rotates a curved tube having a plurality of force adjustment holes. The tube passes through a frame at the upper end of a gas spring, and engaging an adjustment pin on the frame with different adjustment holes changes the amount of resistance. The entire frame above the base can be vertically adjusted to accommodate different sizes of user without altering the relative position between the seat (and user&#39;s hips) and the axis of rotation of the lever arm thus not affecting/changing the designated resistance between users of different heights (resistance is affected when the lever arm is lengthened). The connection between the frame and the base enables the unit to be collapsed to a profile small enough to fit under a bed.

RELATED APPLICATION

The present application claims priority under 35 U.S.C. §119 to U.S.Provisional Application Ser. No. 61/806,319, filed Mar. 28, 2013.

FIELD OF THE INVENTION

The present invention is directed to a collapsible resistance-basedmachine for exercising the core muscles of the body.

BACKGROUND OF THE INVENTION

With widespread awareness of its significant health benefits, regularexercise including progressive resistance strength training has become amatter of high priority to many members of the general public.Progressive resistance strength training is a type of strength trainingthat uses free weights, exercise weight stack machines, compressed air(pneumatics), hydraulic resistance, elastic/rubber bands and gas springsas resistance to strengthen muscles. The key to this type of exercise isadjusting the resistance as the person progresses. A major obstaclefaced by most in following a progressive resistance strength trainingprogram is the lack of readily accessible equipment that enable them toexercise different portions of the body at home. Ideally, an in-home gymfacility is equipped with various exercise machines and implements forexercising different portions of the body but most do not.

The most difficult and overlooked muscles to exercise at home withprogressive resistance are the muscles of the core (transverseabdominal, internal obliques, external obliques, rectus abdominis anderector spinae). These muscles are antagonistic in that they oppose themovement of one another. Proper strength and tone of each muscle groupis important for proper posture, reduction of back injuries and physicalhealth. Despite the importance of the abdominal, and lower back muscles,these muscles tend to be forgotten in most home exercise gyms.Consequently, there is a need for a core exercise machine that usesprogressive resistance, is compact, portable, affordable, and easy touse.

Versatile machines that are reconfigurable to enable various exercisesdo exist. Those machines, however, typically include complexarrangements of mechanical parts and require complicated series ofadjustments to reconfigure the machine for different exercises. Wheresuch complexity is not present, the machines are either undesirablylimiting in the number of different exercises that may be performed onthem, don't allow for any significant resistance, don't offer a widerange of resistance or are physically of such substantial mass anddimensional extent that they may be fully utilized only in certainwide-open areas of a given home, and are hardly movable, let aloneportable. Preferably, an in-home machine with such versatility offers abroad range of progressive resistance, is safe, easy to use, affordable,light weight, and collapsible for storage.

Known exercise machines provide weights or a reaction force as a sourceof resistance (weights are heavy and expensive). Rubber elements used asstretchable resistance bands have been widely used to oppose motion ofcertain mechanisms in an exercise machine (the problem with astretchable band is that the resistance greatly increases as the bandstretches and they tend to dry out and break). Gas springs are known aswell which have a piston/cylinder arrangement. Gas inside the cylinderflows through or around the piston from one side to the other as itmoves back and forth in various designs; usually the piston has one ormore holes or valves in it. The whole cylinder is completely sealed, andwhen the piston rod is inside the cylinder, it takes up room that thegas previously occupied. In other words, when a gas spring is fullypushed in, the gas inside compresses by an amount equal to the volume ofthe piston rod. Furthermore, the net force on the piston is out of thecylinder because the piston rod within the cylinder takes up space andthus there is a pressure differential across the piston. For instance, agas spring in U.S. Patent Publication No. 2005/0101464 provides aresistance force which increases somewhat during compression. Typically,Nitrogen is the working gas inside the gas spring.

Despite numerous exercise machines on the market, there remains a needfor a portable machine that works the core muscles of the body, that cansupply similar resistance to weights yet be safer, portable, moveable,affordable, and which can easily be adjusted for different exercises andusers.

SUMMARY OF THE INVENTION

The present application provides an exercise machine for strengtheningthe core muscles of the body, which consists mostly of the abdominal(transverse abdominal, internal obliques, external obliques, and rectusabdominis) and erector spinae muscles of the back. The machine has arelatively elongated base, and is shaped like an upside down “T” (withthe base as the top of the “T”). The machine is collapsible for storageunder a bed and shipping. The angle of the top vertical bar can beadjusted forward and backward by the user. The top vertical bar can beadjusted to different angles to target the various muscles of the core,to safely limit flexion or extension if needed to avoid discomfort, andit allows for a slimmer profile when collapsing the unit so that it canbe stored under a bed or shipped. The top vertical bar can also beadjusted to properly isolate the desired muscles for a given exercise orlimit range of motion to avoid a painful position for the user. Theheight of the vertical bar can be adjusted to the height of the user'storso. There may also be a foot rest so that the height can be adjustedto match the user's leg length.

In accordance with one preferred embodiment, an exercise machinecomprises a base having at least one upstanding leg at the top of whichis a housing within which a horizontal bar rotates, the housing having aseat firmly mounted thereon such a user can sit on the seat with his orher legs on the ground or on the base. An upstanding lever arm attachesto an end of the horizontal bar displaced from the housing andterminates in a horizontal force application bar. A user sitting in theseat can manipulate the force application bar and rotate the horizontalbar within the housing. A source of adjustable resistance is coupled torotation of the horizontal bar, and an adjustable indexing deviceconnects to the upstanding lever arm for changing the rotationalorientation of the lever arm relative to the horizontal bar. Preferably,the leg and lever arm may be rotated with respect to the base to allowthem to lie substantially flat.

Another exercise machine in accordance with the application includes abase having at least one upstanding leg at the top of which is a housingwithin which a horizontal bar rotates. The housing has a seat firmlymounted thereon such a user can sit on the seat with his or her legs onthe ground or on the base. An upstanding lever arm attaches to an end ofthe horizontal bar displaced from the housing terminates in a horizontalforce application bar. A user sitting in the seat can manipulate theforce application bar and rotate the horizontal bar within the housing.A source of adjustable resistance is coupled to rotation of thehorizontal bar. A height adjustment mechanism between the at least oneupstanding leg and the base permits the upstanding leg to be raisedrelative to the base and changes the height of the seat without alteringthe spacing between the seat and the axis of rotation of the horizontalbar. Preferably, the leg and lever arm may be rotated with respect tothe base to allow them to lie substantially flat. By not having to raisethe seat height for taller users the hips can be maintained close to theC/L of rotation of the lever arm thus mimicking the body's naturalbiomechanics which improves safety and isolates the desired musclegroups. In addition, by raising the vertical bar to adjust the height itminimizes the amount you have to raise the lever arm for taller users,which would otherwise lessen the overall resistance.

A further exemplary exercise machine again has at least one upstandingleg at the top of which is a housing within which a horizontal barrotates. The housing has a seat firmly mounted thereon such a user cansit on the seat with his or her legs on the ground or on the base. Anupstanding lever arm attaches to an end of the horizontal bar displacedfrom the housing terminates in a horizontal force application bar. Auser sitting in the seat can manipulate the force application bar androtate the horizontal bar within the housing. A source of adjustableresistance is coupled to rotation of the horizontal bar, wherein theseat position can be changed relative to the upstanding leg, and whereinin one position the seat is horizontal and positioned for a user toperform abdominal exercises, and wherein in the other position the seatis angled from the horizontal in position for a user to perform backextension exercises. Preferably, the leg and lever arm may be rotatedwith respect to the base to allow them to lie substantially flat. Theseat preferably has two downwardly extending tubes, wherein the seatposition can be changed by engaging one or the other of the downwardlyextending tubes with an upstanding post on the housing.

A still further collapsible exercise machine has at least one upstandingleg at the top of which is a housing within which a horizontal barrotates. The housing has a seat firmly mounted thereon such a user cansit on the seat with his or her legs on the ground or on the base. Anupstanding lever arm attaches to an end of the horizontal bar displacedfrom the housing terminates in a horizontal force application bar. Asource of adjustable resistance couples to rotation of the horizontalbar, and connections between the components of the exercise machinewhich permit it to be collapsed down to a maximum height of 8 inches.

Another exercise machine has at least one upstanding leg at the top ofwhich is a housing within which a horizontal bar rotates. The housinghas a seat firmly mounted thereon such a user can sit on the seat withhis or her legs on the ground or on the base. An upstanding lever armattaches to an end of the horizontal bar displaced from the housingterminates in a horizontal force application bar. A gas spring connectsbetween a fixed point on the upstanding leg and a force adjustment barextending from the horizontal bar. The position of an upper end of thegas spring is adjustable along the force adjustment bar, wherein theprogressivity of the gas spring is 1.1 or less. Preferably, the leg andlever arm may be rotated with respect to the base to allow them to liesubstantially flat.

The machine uses a gas (nitrogen) spring for a constant and consistentresistance force throughout the entire range of motion that is similarto a weight machine. The resistance is variable. The amount ofresistance can be adjusted by changing the angle of the gas spring alongan arc. If the user sits in one direction on the machine the abdominalmuscles can be strengthened and if the user turns around in the otherdirection the lower back muscles are strengthened. The resistance iseasy to switch single-handedly from 10 pounds to 130 pounds, forexample, without getting off the machine and having to move dangerousweight plates.

When strengthening the abdominal muscles the user sits so that the arcis between the users legs. The square mounting tube on the bottom of theseat for the abdominals is used. In this position the seat is horizontaland a majority of the seat (e.g., approximately 8″, and the seat is 12″long) is in front of the central axis of the lever arm. The user sits sothat their hips are in front of the central axis.

When strengthening the muscles of the lower back the user sits so thatthe arc is behind them. The square mounting tube on the bottom of theseat for the lower back is used. In this position the seat is tiltedforward at an angle and a majority of the seat is behind the centralaxis of the lever arm. The user sits so that their hips are in line withthe central axis. The seat is moved from the position in which theabdominals are exercised so that the hips are in line with the centralaxis.

There is a seat belt attached to the undersurface of the seat tostabilize the thighs and isolate the lower back and abdominal muscles.There are foot rests in front and back of the machine to lock the feetinto position. The resistance can be switched single-handedly withoutgetting off the machine and having to move dangerous weight plates.

The exemplary machine provides a portable clinic grade therapeuticexercise device that can be used in a small clinic and also at home. Themachine provides progressive resistance training to the abdominal anderector spinae muscles through a gas spring.

The present application provides an advantage over weight stackmachines: With weight stack machines momentum and gravity cause suddenacceleration in the load being placed on the joints. This application issafer because it provides a consistent resistance at different speedswithout causing unnecessary loading due to gravity and momentum, themachine is space saving, and whereas weights are heavy and noisy, thepresent machine is relatively lightweight and quiet.

The present application provides an advantage over bands: There is amore linear resistance, a variable resistance, and the machine is safer(bands get dry and crack then suddenly break). Plus, bands only provideconsistent resistance in a limited range of motion.

The present application provides an advantage over hydraulic resistancemachines in which one can only push or pull so you are not getting thefull concentric/eccentric contraction which is essential in strengthtraining.

The present application also provides an advantage over compressed air(pneumatics) which are expensive, need an air compressor, heavy, notportable and take up a lot more space.

The present application, which uses a custom made gas spring alsoprovides an advantage over other gas springs, which don't have a verylinear compression factor (the extended force vs. the compressed force)and they have a much lower cycle ability (cycles/minute).

A further understanding of the nature and advantages of the inventionwill become apparent by reference to the remaining portions of thespecification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the present invention will become appreciatedand become better understood with reference to the specification,claims, and appended drawings wherein:

FIG. 1 is a perspective view of an exemplary core exercise machine ofthe present application, while FIG. 1A is an isolated view of a centralhorizontal bar thereof;

FIG. 2 is an end elevational view of the exercise machine of FIG. 1;

FIGS. 3A and 3B are side elevational views of the exercise machine witha user shown operating the machine in two different modes;

FIGS. 4A and 4B are enlarged elevational views looking from the sideopposite that in FIGS. 3A and 3B and showing two different seatpositions for the two different modes, while FIG. 4C shows the seatisolated and the angles of two lower mounting tubes;

FIG. 5 shows the exemplary exercise machine partly collapsed, and FIG. 6shows the exercise machine fully collapsed;

FIGS. 7A and 7B are assembled and exploded views, respectively, of alower height adjustment configuration;

FIGS. 8A and 8B are perspective and side elevational views,respectively, of an alternative exercise machine similar to that shownin FIGS. 1-7 and illustrating the gas spring attached to an adjustmentbar so as to produce relatively high force resistance;

FIGS. 9A and 9B again illustrate the alternative exercise machine withthe gas spring attached so as to produce relatively high forceresistance and a lever arm rotated to a different angle for a differentexercise;

FIGS. 10A and 10B again show the alternative exercise machine with thegas spring attached so as to produce relatively low force resistance;

FIGS. 11A and 11B show the alternative exercise machine with the gasspring attached to produce relatively low force resistance and the leverarm rotated to a nearly horizontal position;

FIGS. 12A and 12B are perspective views of a still further alternativecollapsible exercise machine in accordance with the present inventionwherein the seat and lever arm are supported by multiple legs;

FIGS. 13A-13D are orthogonal views of the multi-leg exercise machine ofFIGS. 12A and 12B;

FIGS. 14A-14C are side elevational views of the multi-leg exercisemachine showing three steps preliminary to collapse thereof;

FIGS. 15A and 15B are perspective and elevational views of the multi-legexercise machine after rotation of a lever arm indexing platepreparatory to collapse;

FIGS. 16A and 16B are perspective and elevational views of the multi-legexercise machine in a state of partial collapse; and

FIGS. 17A-17C are several views of the fully collapsed multi-legexercise machine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates an exemplary exercise machine 20 of the presentapplication that includes an upper frame having a generally vertical leg22 supported on and by a horizontal H-shaped base 24. The base 24comprises a central longitudinal bar 26 welded at both ends to first andsecond lateral bars 28, 30. At least one of the lateral bars 28 includesrubber end caps 32 to prevent movement on solid floors, while the otherlateral bar 30 desirably has a pair of wheels 34 mounted on each end sothat the entire machine 20 can be easily moved.

With reference also to FIGS. 1A and 2, the upper frame of the exercisemachine 20 features a cylindrical horizontal bar 40 attached at the topof the vertical leg 22 and extending laterally therefrom in onedirection. An adjustable lever arm 42 extends upward and comprises alower section 43 fixed to the horizontal bar 40 and an extendablesection 44 movable therein. Preferably, the lever arm 42 and extendablesection 44 are square tubes with the latter having a series of spacedholes 46 that can be registered with a spring-loaded length adjustmentpin 48 that passes in through a single hole formed in the lever arm 42.A horizontal force application bar 50 preferably covered with a foam pad52 attaches firmly to the top of the extendable section 44 and extendslaterally back over the horizontal bar 40, preferably as far as thevertical leg 22. As shown by the movement arrows 54 in FIG. 1, a usercan rotate the force application bar 50 and lever arm 42 about an axiscentered along the horizontal bar 40. The center line C/L of thehorizontal bar 40 defines the axis of rotation of the lever arm 42.

FIG. 1A isolates the horizontal bar 40 so as to explain the manner inwhich the force application bar 50 and lever arm 42 rotate about ahorizontal axis through the top of the vertical leg 22. First of all, ashort tubular fixed housing 60 rigidly attaches (e.g., by welds) at thetop of the vertical leg 22 and contains therein bearings or plasticwashers that enable rotation of an elongated metal inner sleeve withinthe horizontal bar 40. Although not shown, the relatively large innersleeve extends horizontally from one end of the fixed housing 60 throughthe bearings or plastic washers to the opposite end of the horizontalbar 40, with the elongated structure being secured by end bolts 62. Arotatable tubular central section 64 is rotationally fixed with respectto the inner shaft, as is a short tubular force transmission collar 66between the central section 64 and the fixed housing 60. The fixedhousing 60 and force transmission collar 66 are independent of oneanother; the housing 60 does not rotate while the force transmissioncollar 66 does. A wedge-shaped indexing plate 68 fixed rotationally withrespect to the central section 64 extends in a radial plane outwardtherefrom and includes a plurality of adjustment holes 70 formed in anarc oriented about the center line CL. A tubular end section 72 of thehorizontal bar 40 is journaled for rotation about the inner shaft butcan be fixed with respect thereto by engaging an adjustment pin 74spring-mounted on a flange 76 with one of the adjustment holes 70 in theindexing plate 68. That is, the entire structure of the horizontal bar40 rotates within the fixed housing 60 with the angle of the lever arm42 relative to the central section 64 being adjustable by virtue of thepin 74 and holes 70.

With the reference still to FIGS. 1 and 1A, an upstanding flange 80welded to the force transmission collar 66 provides a fastening pointfor an elongated curved tubular bar 82. The bar 82 has a series ofevenly spaced force adjustment holes 84 on an upper generatrix. The bar82 passes through a bracket 86 mounted on the top end of a rod 88. Asseen best in FIG. 4A, the rod 88 extends downward into a cylinder 90which is pivotally mounted toward its lower end on a bracket 92 fixed toa lower end of the vertical leg 22. In a preferred embodiment, the rod88 is desirably positioned below the cylinder 90 so that the internalseal around the rod stays lubricated, such as seen in the alternativeembodiment of FIGS. 8-11.

Again with reference to FIG. 1, the upper end of the rod 88 can be fixedwith respect to a position along the curved bar 82 by engaging aspring-loaded adjustment pin 94 mounted in the bracket 86 in one of theadjustment holes 84. The rod 88 and cylinder 90 preferably comprise anitrogen gas spring 95, although other force resistance devices can beutilized. A gas spring supplies a constant force resembling weights.Indeed, the preferred gas spring 95 has a relatively low progressivityof 6-11%, preferably 7-8%, which means that if you start out at 100 lbsof resistance, as the gas spring compresses the resistance goes up to106-108 lbs of force. Such a gas spring is available from Taizhou XindaGas Spring Co., Ltd, although other suppliers are available. Most stocksprings have a progressivity of between 20-40%. It should be understood,however, that various features of the exercise machine 20 describedherein are useful with a conventional gas spring, or even withoutincluding a gas spring, and therefore a spring resistance device orother such mechanism can be substituted.

Also, none of the previous stock gas springs are made for using at morethan 6 cycles per minute, while the gas springs disclosed herein can beused up to 18-20 cycles per minute due to the quality of the seals.

When the user rotates the horizontal bar 40, including the forcetransmission collar 66 and flange 80 as seen in FIG. 1A, the curved bar82 rotates as well, which alternately moves the rod 88 in and out of thecylinder 90. As explained above, a gas spring 95 provides resistance tomovement of the rod 88 in both directions. The user can adjust theresistance significantly (e.g., 10 lbs to about 130 lbs) for usedepending on which one of the adjustment holes 84 the adjustment pin 94engages. That is, the change in lever arm distance from moving thebracket 86 along the curved bar 82 changes the resistance. Generallyspeaking, the lower down on the curved bar 82 that the upper end of therod 88 engages the greater the resistance to rotation of the lever arm42. Vice versa, moving the adjustment pin 94 up on the curved bar 82toward the centerline C/L reduces the resistance. Optionally, a secondgas spring in parallel with or in place of the first may be added tosupply more resistance.

FIGS. 3A and 3B show the exercise machine 20 with a user operating themachine in two different training modes—back extension (erector spinaemuscles) and flexion (abdominal muscles). For strengthening the obliquemuscles the positioning is the same as in FIG. 3B for the rectusabdominus, but the user turns his/her body at an angle between 0-90degrees. The user switches between the two primary modes of operation bymoving a seat 100 into two different positions over the fixed housing 60in order to displace the axis of rotation of the user's hips inrelationship to the machine's axis of rotation. FIGS. 3A and 3B indicatethe different centers of hip rotation, the former essentially directlyabove the centerline C/L of the horizontal bar 40 and the latter shiftedhorizontally to one side. This conversion enables a more biomechanicallycorrect position when strengthening the abdominal and erector spinaemuscles. Although not shown in FIGS. 3A and 3B, a seat belt 101 (FIG. 2)fixed under the seat 100 may be provided and utilized in either exercisemode to help isolate the targeted muscles and prevent the recruitment ofundesired muscles.

FIG. 1A and also FIGS. 4A and 4B (looking from the direction opposite toFIGS. 3A and 3B) show a short square post 102 welded to the fixedhousing 60 at a slight angle to the vertical, preferably between about5-15°, and more preferably about 8°. FIG. 4C shows the seat 100 isolatedand two square mounting tubes 104, 106 projecting downward therefrom atangles from the vertical, α and β, which are preferably the same (α=β).In FIGS. 3A and 4A a first mounting tube 106 engages the square post 102such that the seat 100 assumes an angle θ with the horizontal, which ispreferred for the back extension exercises. The angle θ is desirablybetween about 15-20°, and more preferably is about 16°. Conversely, asseen in FIGS. 3B and 4B, the second mounting tube 104 engages the squarepost 102. In this configuration, the seat 100 is horizontal, or withinabout 5° of horizontal, which is preferred for the abdominal exercises.Therefore, the angle θ is approximately the same as the angle at whichthe square post 102 extends up, which is between about 5-15°, and morepreferably about 8°. Also, the angle a plus the angle at which thesquare post 102 extends upward (preferably about) 8°) together make upthe angle θ that the seat makes in the back extension position.Therefore, since in the preferred embodiment the angles α=β, and β ispreferably about 8°, in a preferred embodiment the angle θ equals about16°.

FIG. 5 shows the exemplary exercise machine 20 partly collapsed, andFIG. 6 shows the exercise machine fully collapsed. Collapsed, theexercise machine 20 will be no more than 8″ tall and preferably 7″ orless, and thus will be able to fit under most beds. The lever arm 42 canbe rotated to lie substantially horizontally by disengaging thespring-mounted adjustment pin 74 from the adjustment holes 70 in theindexing plate 68. Also, the gas spring 95 can be pivoted down tohorizontal about its lower pivot point by disengaging the spring-loadedadjustment pin 94 in the bracket 86 from the adjustment holes 84 in thecurved bar 82. Collapse of the upper components of the machine 20 overthe base 24 is explained below.

Advantageously, the exercise machine 20 can be adjusted to the legheight of the user to allow for optimum biomechanics and reduce the riskof injury. FIGS. 7A and 7B are assembled and exploded views,respectively, of a lower height adjustment assembly. The vertical leg 22is supported on and by the central longitudinal bar 26 of the base 24.An upwardly-opening square hole 110 is formed in the middle of the bar26 into which fits a reduced-size lower end section 112 of the verticalleg 22. The end section 112 has a reduced size relative to the rest ofthe leg 22 and passes through a height adjustment collar 114 positionedjust above the bar 26. The end section 112 has a series ofvertically-spaced holes 116 that register with a single hole 118 in thecollar 114 such that a pin 120 can fix their relative positions.Removing the pin 120 and shifting the vertical leg 22 up or down enablesadjustment of the height of the components of the machine 20 above thebase 24. This enables adjustment of the height of the seat 100 fordifferent sizes of users, and also maintains the relative positionbetween the seat 100 and the centerline C/L of the horizontal bar 40,which allows for optimum biomechanics, as seen in FIG. 2. This enablesheight adjustment without lengthening the lever arm and altering theresistance profile. Desirably, the height of the upper frame can beadjusted at least about 2 inches, and more preferably between 2-4inches.

For the purpose of collapsing the machine 20, the vertical leg 22 iseasily disengaged from the base 24 by virtue of the adjustment collar114. More specifically, the collar 114 has a pair of longitudinalflanges 122 spaced apart about the same lateral width as the lower basebar 26, and flanking the same. Holes 123 in the flanges 122 line up withholes 124 in the bar 26, and pins 126 extend through both flanges andthe bar to secure the collar 114 in place. During collapse of themachine 20, the pin 126 closest to the square hole 110 is removedallowing the upper structure to rotate about the other pin, as seen inFIG. 5. Eventually, the vertical leg 22 rotates to lie substantiallyhorizontally over the lower bar 26, as seen in FIG. 6. A small bumper orspacer 128 attaches to the leg 22 and extends horizontally in thedirection opposite the gas spring mechanism. The spacer 128 contacts thebase bar 26 when the machine collapses and the distance the spacer jutsout from the leg 22 is sufficient to prevent contact between componentsof the horizontal bar 40 and the base 24, as well as maintaining thegenerally horizontal low-profile orientation of the leg 22 whencollapsed down. The spacer 128 is desirably elastomeric to reduce thenoise when collapsing the structure and also to prevent marring the basebar 26.

Once the vertical leg 22 lies substantially horizontally over the lowerbar 26, the lever arm 42 rotates to lie substantially horizontally aswell, as does the gas spring 95, as shown. FIG. 2 illustrates how thesecomponents are offset laterally from one another so as to avoidinterfering with their respective collapse. The seat belts 101 may beused to wrap around the entire structure to hold the componentsgenerally together, or a separate band or strap may be provided for thispurpose.

FIGS. 8-11 schematically illustrate an alternative collapsible exercisemachine 220 similar to that shown in FIGS. 1-7, but with several smalldifferences. The exercise machine 220 again features an upper framehaving a generally vertical leg 222 supported on and by a horizontalH-shaped base 224. The upper frame includes an adjustable lever arm 242that is mounted to rotate with a horizontal bar (not shown) as describedabove. The angle of the lever arm 242 can be adjusted by moving a pin244 between an array of holes 246 provided in an indexing plate 248 (seeFIG. 8B). A horizontal force application bar 250 preferably covered witha foam pad 252 attaches firmly to the top of the lever arm 242 andextends laterally back over the horizontal bar and over a seat 254,preferably as far as the vertical leg 222. As with the first embodiment,a user can rotate the force application bar 250 and lever arm 242 aboutan axis centered along the horizontal bar. The center line C/L of thehorizontal bar 240 defines the axis of rotation of the lever arm 242.

The lever arm 242 is rotationally fixed with respect to a forceadjustment bar 260 that depends downward below the seat 254 having aplurality of adjustment holes along its length. An upper end of a gasspring 262 fastens to one of the adjusted holes using a pin or nut andbolt 264. A lower end of the gas spring 262 is pivotally connected via apin or nut and bolt 266 to an upstanding post 268 on the base 224. Itcan thus be seen the rotation of the lever arm 242 causes rotation ofthe force adjustment bar 260, and the amount of resistance forceimparted by the gas spring 262 depends on where the spring is connectedalong the bar.

FIGS. 8A and 8B illustrate the gas spring 262 attached to the distal endof the adjustment bar 260 so as to produce relatively high forceresistance. Furthermore, the pin 244 is placed in one of the holes 246in the indexing plate 248 so as to maximize the angle between the leverarm 242 and the force adjustment bar 260. The lever arm 242 is adjustedto an obtuse angle 270 from the horizontal, so the user can sit on theseat 254 and perform back extension (erector spinae muscles) or flexion(abdominal muscles) exercises. FIGS. 9A and 9B illustrate the sameconfiguration after the lever arm 242 is rotated to an acute angle 272,thus fully compressing the gas spring 262. The reader will understandthat repositioning the lever arm 242 in a clockwise direction relativeto the indexing plate 248 will increase the user's leverage and reducethe amount of force needed to rotate the lever arm 242. Likewise, movingthe upper end of the gas spring 262 along the adjustment bar 260 towardits axis of rotation (the same as the center line C/L) will reduce themoment arm and increase leverage.

FIGS. 10A and 10B again show the alternative exercise machine 220 withthe gas spring 262 attached so as to produce greater leverage andrelatively low force resistance. More particularly, the upper end of thegas spring 262 pivotally attaches to a hole in the force adjustment bar260 closest to its axis of rotation. Also, the pin 244 has been movedclockwise along the holes in the indexing plate 248 to reduce the anglebetween the lever arm 242 and adjustment bar 260. The lever arm 242 isshown at an obtuse angle 274 to the horizontal in FIG. 11A. Afterclockwise rotation of the lever arm as seen in FIG. 11B, the gas spring262 is compressed, though not as far as in FIGS. 9A and 9B.

FIGS. 12-17 illustrate an alternative exercise machine 300 which is aplurality of support legs, in contrast to the single generally verticalleg 22 extending up from the base 24 in the earlier embodiments. Notonly will multiple legs increase stability, but as will be shown theexercise machine 300 can easily collapse. Several features describedabove with regard to the first embodiment are not shown in thealternative exercise machine 300 for clarity, though such features couldeasily be included.

FIGS. 12A and 12B are perspective views of the exercise machine 300wherein a seat 302 and lever arm 304 are supported by multiple legs 306,308 over a base 310. The base 310 includes a generally U-shaped memberand two of the support legs 306 are pivotally mounted outside of thefree ends thereof. The other two support legs 308 are pivotally mountedinside of the U-shaped base 310 and approximately halfway to the closedend thereof. As seen also in FIGS. 13A-13D, upper ends of the legs 306,308 are pivotally mounted to a generally square frame 312 under the seat302. Although not shown, the rotational position of each of the legs306, 308 may be locked with respect to both the base 310 and the frame312 via locking pins or the like. In the configuration of FIGS. 12-13,the legs 306, 308 are locked at 90° with respect to both the base 310and the frame 312 such that the exercise machine 300 is in its uprightand functional configuration.

The lever arm 304 rotates as described earlier about a horizontal bar(not shown) mounted under one end of the seat 302. The angle of thelever arm 304 with respect to the horizontal bar may be altered bymoving a pin 320 within an array of holes in an indexing plate 322. Asseen best in FIG. 13A, a force adjustment bar 324 depends down from thehorizontal bar and has a series of holes therein. An upper end of a gasspring 326 pivotally attaches to one of the holes using a pin or nut andbolt combination. A lower end of the gas spring 326 pivotally attachesto a lower front corner of the base 310, such as via a pivot rod 328 asseen in FIGS. 12A and 12B. Aside from the multiple legs 306, 308, theexercise machine 300 functions much like the earlier embodiment, whereinthe amount of force may be adjusted as well as the angle of the leverarm 304.

FIG. 14A illustrates an exemplary height H from the ground to the seat302. In a preferred embodiment, the height H is between 18-22 inches(45-56 cm), more preferably about 20 inches (50 cm). The length L of theframe 310 is between about 30-36 inches (76-91 cm), and more preferablyabout 34 inches (86 cm).

FIGS. 14B-14C are side elevational views of the multi-leg exercisemachine 300 showing three steps preliminary to collapse thereof. First,the lever arm 304 is decoupled from the force resistance assembly byremoving the pin 320 from the indexing plate 322, as seen in FIG. 14B.The lower end of the gas spring 326 is then detached from its pivot rod328 (FIG. 12A) and both the lever arm 304 and gas spring are alignedhorizontally, as in FIG. 14C. Note the force adjustment bar 324projecting out from under the seat 302.

Next, as seen in FIGS. 15A and 15B, the force adjustment bar 324 isrotated about 180° underneath the seat 302. By virtue of the fixednature of the force assembly, this also rotates the indexing plate 322from above to below the lever arm 304. FIG. 15B shows an exemplarydimension of the height h from the top of the seat 302 to the lower edgeof the indexing plate 322. As will be seen, this height h defines theheight to which the exercise machine 300 can be collapsed, and isdesirably less than 8 inches (20 cm), and more preferably less than 7inches (18 cm). In one embodiment, the height h is about 6.25 inches (16cm).

FIGS. 16A and 16B are perspective and elevational views of the multi-legexercise machine 300 in a state of partial collapse. The pivot points atthe top and bottom of each leg 306, 308 are unlocked to enable thiscollapse. The outer legs 306 fold down on the outside of the frame 310,and the inner legs 308 fold down on the inside thereof.

Finally, FIGS. 17A-17C show the fully collapsed multi-leg exercisemachine 300. Again, by virtue of the laterally offset positions of thevarious components, as seen in FIG. 13C and 13D, they all fold down tolie in essentially the same plane. A strap or bag may be provided toprevent the assembly from opening up, or the locking mechanism at thetop and bottom of each leg 306, 308 may also secure them in theircollapsed configuration.

Although the invention has been described and illustrated with a certaindegree of particularity, it is understood that the present disclosurehas been made only by way of example, and that numerous changes in thecombination and arrangement of parts can be resorted to by those skilledin the art without departing from the scope of the invention, ashereinafter claimed.

What is claimed is:
 1. An exercise machine, comprising: a base having atleast one upstanding leg at the top of which is a housing within which ahorizontal bar rotates, the housing having a seat firmly mounted thereonsuch a user can sit on the seat with his or her legs on the ground or onthe base; an upstanding lever arm attached to an end of the horizontalbar displaced from the housing terminates in a horizontal forceapplication bar, wherein a user sitting in the seat can manipulate theforce application bar and rotate the horizontal bar within the housing;a source of adjustable resistance to rotation of the horizontal bar; andan adjustable indexing device connected to the upstanding lever arm forchanging the rotational orientation of the lever arm relative to thehorizontal bar.
 2. The machine of claim 1, wherein the adjustableindexing device comprises an indexing plate that is fixed with respectto the horizontal bar and projects radially away therefrom adjacent thelever arm, and wherein an adjustment pin fixed to the lever arm fits inone of an array of indexing holes in the indexing plate to change therotational orientation of the lever arm relative to the horizontal bar.3. The machine of claim 1, further including a height adjustmentmechanism between the at least one upstanding leg and the base whichpermits the upstanding leg to be raised relative to the base and changesthe height of the seat without altering the spacing between the seat andthe axis of rotation of the horizontal bar.
 4. The machine of claim 1,wherein the seat position can be changed relative to the upstanding leg,and wherein in one position the seat is horizontal and positioned for auser to perform abdominal exercises, and wherein in the other positionthe seat is angled from the horizontal in position for a user to performback extension exercises.
 5. The machine of claim 1, wherein the machineis collapsible wherein the leg and lever arm may be rotated with respectto the base to allow them to lie substantially flat having a maximumheight of 8 inches.
 6. The machine of claim 1, wherein the source ofadjustable resistance comprises a gas spring connected between a fixedpoint on the upstanding leg and a force adjustment bar extending fromthe horizontal bar, wherein a position of an upper end of the gas springis adjustable along the force adjustment bar.
 7. The machine of claim 1,wherein the progressivity of the gas spring is 1.1 or less.
 8. Themachine of claim 1, wherein there are four upstanding legs.
 9. Anexercise machine, comprising: a base having at least one upstanding legat the top of which is a housing within which a horizontal bar rotates,the housing having a seat firmly mounted thereon such a user can sit onthe seat with his or her legs on the ground or on the base; anupstanding lever arm attached to an end of the horizontal bar displacedfrom the housing terminates in a horizontal force application bar,wherein a user sitting in the seat can manipulate the force applicationbar and rotate the horizontal bar within the housing; a source ofadjustable resistance to rotation of the horizontal bar; and a heightadjustment mechanism between the at least one upstanding leg and thebase which permits the upstanding leg to be raised relative to the baseand changes the height of the seat without altering the spacing betweenthe seat and the axis of rotation of the horizontal bar.
 10. The machineof claim 9, wherein there is a single upstanding leg, and wherein theheight adjustment mechanism comprises a lower end of the leg insertedinto an aperture in the base and having an indexing mechanism to adjustthe relative insertion depth.
 11. The machine of claim 9, wherein themachine is collapsible wherein the leg and lever arm may be rotated withrespect to the base to allow them to lie substantially flat, and furtherincluding an adjustment collar through which the lower end of the leginserts, the adjustment collar having a pair of longitudinal flangesflanking the base, wherein holes in the flanges line up with holes inthe base, and pins extend through both flanges and the base to securethe collar in place, and wherein one of the pins may be removed to allowthe adjustment collar and leg of the exercise machine to rotate aboutthe other pin, thus facilitating collapse of the machine.
 12. Themachine of claim 9, wherein the seat position can be changed relative tothe upstanding leg, and wherein in one position the seat is horizontaland positioned for a user to perform abdominal exercises, and wherein inthe other position the seat is angled from the horizontal in positionfor a user to perform back extension exercises.
 13. The machine of claim9, wherein the machine is collapsible wherein the leg and lever arm maybe rotated with respect to the base to allow them to lie substantiallyflat having a maximum height of 8 inches.
 14. The machine of claim 9,wherein the source of adjustable resistance comprises a gas springconnected between a fixed point on the upstanding leg and a forceadjustment bar extending from the horizontal bar, wherein a position ofan upper end of the gas spring is adjustable along the force adjustmentbar.
 15. The machine of claim 9, wherein the progressivity of the gasspring is 1.1 or less.
 16. An exercise machine, comprising: a basehaving at least one upstanding leg at the top of which is a housingwithin which a horizontal bar rotates, the housing having a seat firmlymounted thereon such a user can sit on the seat with his or her legs onthe ground or on the base, wherein the seat engages an upstanding poston the housing; an upstanding lever arm attached to an end of thehorizontal bar displaced from the housing terminates in a horizontalforce application bar, wherein a user sitting in the seat can manipulatethe force application bar and rotate the horizontal bar within thehousing; and a source of adjustable resistance to rotation of thehorizontal bar, wherein the seat position can be changed relative to theupstanding post, and wherein in one position the seat is horizontal andpositioned for a user to perform abdominal exercises, and wherein in theother position the seat is angled from the horizontal in position for auser to perform back extension exercises.
 17. The machine of claim 16,wherein the seat has two downwardly extending tubes and the seatposition can be changed by engaging one or the other of the downwardlyextending tubes with the upstanding post on the housing.
 18. The machineof claim 16, wherein the machine is collapsible wherein the leg andlever arm may be rotated with respect to the base to allow them to liesubstantially flat having a maximum height of 8 inches.
 19. The machineof claim 16, wherein the source of adjustable resistance comprises a gasspring connected between a fixed point on the upstanding leg and a forceadjustment bar extending from the horizontal bar, wherein a position ofan upper end of the gas spring is adjustable along the force adjustmentbar.
 20. The machine of claim 16, wherein the progressivity of the gasspring is 1.1 or less.